Piston ring



Oct. 20, 1936. F. D. DURHAM 2,057,940

" PISTON RING Filed June 24, 1935 Patented Oct. 20, 1936 UNITED STATES PISTON RING Fred D. Durham, Louisville, Ky.,- assignor to 0.

Lee Cook Manufacturing Company, Louisville, Ky., a corporation of Kentucky Application June 24, 1935, Serial No. 28,182

1 Claim. (01. 309 -29) The present invention relates to piston rings, and the object isto provide a ring made up of cooperating members in which fluid under pressure is admitted behind the ring for the purpose" 5 of expanding it and keeping it in proper contact with the cylinder wall, and yet the members are so related that this expansion is limited and the danger of a member being expanded or sprung into a port of the cylinder wall passing the same is reduced to a minimum.

In the accompanying drawing: I

Figure 1 is a longitudinal sectional view through a portion of an engine cylinder showing a part of the piston therein, and illustrating two of the rings in place, one in elevation and the other in section.

Figure 2 is a perspective view showing the undersidepf the ring assembly. Figure 3 is a detail perspective view showing the open passageway between the ends of the upper ring member. I

Figure 4 is a detail sectional view illustrating the manner in which the fluid under pressure is admitted behind the ring- 2 Figure 5 is a sectional view showing the joint of the lower ring member sealed against the passage of motive fluid.

In the embodimentdisclosed the pistonring consists of an upper ring member 6 and a lower ring member I placed face to face. One of these members, as the lower, is provided with a longitudinal tongue 8 on its upper face, and the opposing lower face of the upper member is pro-, vided with a corresponding groove 9 that receives the tongue. Both ringmembers are of spring metal, and are split so that they may expand and contract, and consequently have their endsspaced apart. The space l0 between the ends ll of the upper member is unobstructed. This member, it being understood, is on the pressure side of the piston. The space l2 between'the ends or the lower member is, however, sealed, and for this purpose the upper member'is provided with 8. depending flange l3 which bridges -the said space ii. The inner sides of the ends it of the lower member 1 are cut away, as shown at l5 to receive the ends of the said flange i3, and consequently slidably lap said flange. As shown the comers it of said ends i4 and th orners ll of the ends ll are'preferably r0 ded off so that they will not cut or score the cylinder wall.

with this structure, it will be evident that considering the so-called upper ring member as the 'member which faces the pressure side of the 65 that when pressure is on the piston the fluid which may pass between the piston and cylinder wall, respectively designated A and B can flnd its wa; between the ends ll of the member 6 to co the rear or inner side of the piston ring, and

piston, it will be evident by reference to'Fig'ure 4 thus expand the ring' assembly outwardly against the cylinder wall. On the other hand, the space it between the ends it of the lower member I is sealed by the flange i3 and consequently there can be no escapeof this fluid under pressure at 6 this point. t

There is a peculiar interrelation in this arrangement with the interlocking of the two members by the tongue and groove formation, in that while expansion ,of the ring assembly is per- 1 mitted, there can be no excessive expansion of one of the ring members, with respect to the other,

and consequently one acts as a resisting member for the other, so that the danger of one ring member being pressed out or expanded or sprung 15 into a port while passing the same, with consequent injury to the parts, is avoided.

It moreover avoids the necessity of the use of dowels for holding the ring members against relative movement. The use of dowels is an expensive item, and it is diiiicult to secure them in place. Furthermore the action ofthe ring members frequently shears the dowel, causing cylinder scoring and uneven groove wear.

-In the present structure the ringassembly is free to adjust its position in the ring groove, as

such adjustment is made necessary by irregularities of the cylinder bore. This freedom of movement not only eliminates uneven groove wear. but has the advantages of allowing the lower ring surface to lap itself into the groove landing, thus providing a more efficient and effective seal.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description, and it will be understood that various changes in the size, shape, proportion and-minor details of'construction may be resorted 'to with- .out departing from the spirit or sacrificing any of the advantages of the invention. What I claim is:

A piston ring comprising spring ring members, one of which has a longitudinal tongue on one of its side faces, the other having in its opposing face a longitudinal groove to receive the tongue, said ring members being split, one of the ring members having a sealing flange on its inner side that extends acrossthe space between the ends of the other-ring member and has said ends slidableupon the end portions ofthe flange, the space between the ends of said flange carrying member being open to the passage of fluid under pressure therethrough and to the back of the ring assembly, the ends of said rings having rounded outer corners said ring members being relatively rotatable one on the other, and said members being-limited in said relative rotation by the sealing flange. Y

man I); DURHAM. 

